Laser ablation has been used to produce piezoelectric films for use in a low voltage cantilever bimorph actuator structure. Nd doped lead zirconium titanate (PZT) films were deposited by a pulsed Q-switched Nd:YAG laser (wavelength 1064 nm) on to unheated silver-coated oxidised silicon substrates at a distance of 30 mm between substrate and target. Growth rates were typically 20 Å/s. The as-deposited PZT films were amorphous but contained small microcrystalline pyrochlore and perovskite regions. Optimisation of the annealing conditions resulted in perovskite as the main phase (T=750°C, t=2 h). A special fabrication technique (PbO covered PZT) was used to minimise film defects mainly caused by large particles.
In order to improve the density of the film and deposition rates of the ablated PZT film, ablations using an XeCl excimer laser (wavelength 308 nm) under the influence of a static magnetic field were also studied. The decreased particle size in the deposited films showed that the surface quality of the films fabricated by the excimer laser was better than that of films deposited by the Nd:YAG laser. Films were studied using EDS, XRD and also micro-Raman spectrometry.
Bimorph cantilever element structures were realised using Nd:YAG laser ablation. DC bending characteristics of these low voltage cantilever bimorphs were measured as a function of voltage using a Michelson interferometer. Displacements in the order of microns were obtained from a 15 mm x 4 mm x 80 �ement with a driving voltage level of 10 V.